In an IEEE 802.11 wireless local area network (WLAN) standard, an access point (AP) controls network management of all stations. When a station moves in the coverage zone of an AP, it will first perform a number of network establishment procedures to join the network controlled by the AP. The network establishment procedures include scanning, synchronization, authentication and association. Then the communication or data transfer between the station and the network can start. In other words, for an AP to broadcast any application data to a station, the station needs to establish a network connection first. See, for example, ISO/IEC 8802-11 ANSI/IEEE Standard 802.11 Specification, 2003, the content of which is hereby expressly incorporated by reference herein.
Management frames are exchanged between an AP and a station for implementing network establishment procedures. One management frame type in the IEEE 802.11 standard (802.11) is the beacon frame that is transmitted periodically by an AP to allow stations to locate and identify an 802.11 WLAN. The beacon frame includes parameters that are related to the lower protocol layers (medium access control layer and physical layer). However, there is no defined field in the beacon frame for upper protocol layers to broadcast information or transmit application-specific data that trigger applications in stations.